Historically, projection engines of projection systems have been designed employing high intensity discharge lamps. These prior art projection engines/systems suffer from a number of disadvantages. For examples, the lamps typically have relatively short lives, and reduced brightness after an initial period of usage. Further, there is an appreciable period of waiting for the lamp to warm up, when a projection engine/system is first turned on. During that period, either no image is available or the available images are of poor quality. Additionally, active cooling arrangements are typically required to dissipate the heat created during operation.
Resultantly, there has been a lot of interest in developing and manufacturing in a mass scale projection engines and projection systems employing solid state light sources. Such engines/systems typically either do not have or have the aforementioned disadvantages in a lesser degree. Examples of solid state light sources include but are not limited to light emitting diodes (LED), laser diodes and so forth.
FIG. 1 illustrates a plane view of a typical solid state light source and micro mirror light valve based projection system architecture. The plane view may be a top view or a side view of the projection system. As illustrated, solid state light source based projection system 100 includes a number of primary color solid state light sources, such as LED 102-106 sourcing red (R), green (G) and blue (B) lights respectively. LED 102-106 are arranged in an orthogonal manner, respectively disposed on 3 sides of prism or dichroic combiner 108. Prism or dichroic combiner 108 is employed to combine the lights emitted by LED 102-106. Further, light integrator 110 is placed in the light path to enhance the combined light. Mirror 112 is employed to reflect the enhanced light onto micro mirror device 114.
Micro mirror device 114 includes a number of micro-mirrors that may be individually tilted to an “on” or an “off” position to selectively reflect the enhanced light reflected from mirror 112 towards projection lens 116 (“on”) or away from projection lens 116 (“off”). Resultantly, with each micro mirror corresponding to a pixel, and by selectively controlling their positions, an image or a series of images, including a series of images forming a motion picture, may be projected.
While the architecture of FIG. 1 works well, it is nevertheless desirable to further improve on reducing the cost and/or increasing reliability of the next generation of projection engines and projection systems.